The new pyridineâamine ligand, meophdpa (bis(dipyridylmethyl)-4-methoxyaniline) was synthesised and reacted with copper(II) perchlorate. The X-ray crystal structure of the resulting complex revealed a monomeric copper(II) site, with the copper bound to the three ligand nitrogens in a relatively unusual meridional fashion, as well as a chloride and a water molecule. The sixth coordination site was, unexpectedly, occupied by a phenyl ring hydrogen atom.



Graphical abstract



A new pyridineâamine ligand has been prepared and its reaction with copper perchlorate characterised. An interesting phenyl-HâCu interaction was observed

Creaven, Bernadette

Mahon, Mary

McGinley, John

Moore, Ann-Marie

English

MURAL - Maynooth University Research Archive Library

www.elsevier.com/locate/inocheInorganic Chemistry Communications 9 (2006) 231–234Copper(II) complex of a tridentate N-donor ligand with unexpectedCu–H interactionBernadette S. Creaven a, Mary F. Mahon b, John McGinley c,*, Ann-Marie Moore aa Department of Applied Science and Advanced Smart Materials Research Centre, Institute of Technology, Tallaght, Dublin 24, Irelandb Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, England, United Kingdomc Department of Chemistry, National University of Ireland Maynooth, Maynooth, Co. Kildare, IrelandReceived 19 October 2005; accepted 13 November 2005Available online 20 December 2005AbstractThe new pyridine–amine ligand, meophdpa (bis(dipyridylmethyl)-4-methoxyaniline) was synthesised and reacted with copper(II) per-chlorate. The X-ray crystal structure of the resulting complex revealed a monomeric copper(II) site, with the copper bound to the threeligand nitrogens in a relatively unusual meridional fashion, as well as a chloride and a water molecule. The sixth coordination site was,unexpectedly, occupied by a phenyl ring hydrogen atom. 2005 Elsevier B.V. All rights reserved.Keywords: Tridentate pyridine–amine ligand; Synthesis; Copper(II) complex; X-ray crystal structure1 Meophdpa.HCl: %yield = 78.5%; Found: C, 60.79%, H, 6.24% N,11.10%; Calc. for C19H21Cl2N3O: C, 60.32%, H, 5.60% N, 11.11%; dH(300 MHz, CDCl3): 8.71 (d, 2H, J = 6.8 Hz, py-H6), 8.01 (t, 2H,J = 6.8 Hz, py-H4), 7.69 (d, 2H, J = 6.8 Hz, py-H3), 7.51 (t, 2H,J = 6.8 Hz, py-H5), 6.79–6.73 (m, 4H, Ph-H), 5.01 (s, 2H, CH2), 3.99 (s,3H, OMe); dH (300 MHz, d6-DMSO): 8.93 (d, 2H, J = 6.8 Hz, py-H6),8.24 (t, 2H, J = 6.8 Hz, py-H4), 7.81 (d, 2H, J = 6.8 Hz, py-H3), 7.68 (t,The design and construction of supramolecular architec-tures has been a rapidly developing area in the past numberof years [1]. Indeed, the last decade has witnessed a surge ofinterest in the discovery of simple building blocks capableof forming specific molecular arrays under certain chemicalconditions [2]. For bio-inorganic model complexes, thedesign and synthesis of the ligand is perhaps the mostimportant step in the modelling process. Control of thenumber and type of coordinating atoms is key to achievingmetal complexes that mimics the coordination sphere andreactivity of metal-containing enzymes.As part of our continuing research, we have previouslyreported upper and lower rim functionalised calix[4]arenes,capable of binding transition metal and alkali metal salts[3]. One such calix[4]arene contained picolyl groups [3a].In extending this theme, we targeted the design of ‘‘pre-ligands’’, capable of having two or three donor atomspresent, with a view to attaching these to the lower rimof the calix[4]arene and thereby forming di-or tri-nuclearmetal complexes. The compounds chosen as pre-ligands1387-7003/$ - see front matter  2005 Elsevier B.V. All rights reserved.doi:10.1016/j.inoche.2005.11.008* Corresponding author. Tel.: +353 1 708 4615; fax: +353 1 708 3815.E-mail address: john.mcginley@nuim.ie (J. McGinley).were derivatives of bis(2-pyridylmethyl)amine (dpa) andare shown in Fig. 1. The related analogue of the ligands(R@H in Fig. 1, phdpa) has been previously reported byMcKenzie et al. [4]. This paper reports the attempted syn-thesis of these pre-ligands and an X-ray crystallographi-cally characterised copper(II) derivative containing one ofthem.Ligands meophdpa1 and hophdpa were, respectively,prepared by nucleophilic substitution of (2-chloro-methyl)pyridine with 4-methoxyaniline or 4-aminophenolin a water–dichloromethane system, in a manner analogousto that previously described [4]. While the ligand meop-2H, J = 6.8 Hz, py-H5), 6.72 (d, 2H, J = 6.8 Hz, o-Ph-H), 6.50 (d, 2H,J = 6.8 Hz, m-Ph-H), 5.05 (s, 2H, CH2), 3.58 (s, 3H, OMe); dC (300 MHz,CDCl3): 156.7, 153.6, 145.4, 141.3, 140.7, 124.0, 123.8, 116.6, 115.0, 56.4,55.5; ESMS: m/z 306.4, (meophdpa + H); C19H19N3O requires 305.37.NOH NHFig. 2. Ligand obtained from reaction of 4-aminophenol with (2-chloromethyl)pyridine.NN NOMeH HFig. 3. Alternative structure of meophdpa showing potential interactionbetween pyridyl nitrogens and phenyl ring.RNN NFig. 1. Ligands chosen for synthesis; meophdpa, R@OMe; hophdpa,R@OH.232 B.S. Creaven et al. / Inorganic Chemistry Communications 9 (2006) 231–234hdpa was obtained as a solid in good yield, the second syn-thesis of hophdpa only gave a monosubstituted aniline,hophmpa, as shown in Fig. 2. Complexation studies of thisligand will be reported elsewhere. The ligand meophdpawas isolated as the di-hydrochloride salt, as confirmed bythe elemental analysis. No attempt to remove the HCl fromthe ligand was undertaken prior to complexation reactions.The 1H NMR spectrum of meophdpa was obtained in bothCDCl3 and d6-DMSO. The spectra exhibited the same sig-nal distribution with the exception of the phenyl protons,which appeared as a multiplet in the CDCl3 but as two dis-tinct doublets in the case of the d6-DMSO spectrum. Thissuggests that, in the DMSO solution, there was an interac-tion of the pyridyl nitrogens with the ortho-hydrogens ofthe phenyl ring (see Fig. 3). McKenzie et al. [4] report asimilar pattern in the phdpa compound but make no com-ment on this possible interaction.The reaction of the ligand, meophdpa.2HCl, with cop-per(II) perchlorate hexahydrate in methanol in a 2:1 ratio,resulted in the formation of a metal complex. [Caution!Although no problems were encountered in the preparationof the perchlorate salts, suitable care should be taken whenhandling such potentially hazardous compounds.] Elementalanalysis for the complex2 suggested the presence of a 1:1metal–ligand complex, instead of the anticipated 1:2 stoi-chiometry generally observed for complexes of ligands ofthis general type [4,7,8]. The product was isolated as bluecrystals from a suitable sample was selected for an X-raystructure determination.2 [Cu(meophdpa)Cl(H2O)2](ClO4): %yield = 91.5%; Found: C, 48.24%,H, 5.24% N, 9.10%; Calc. for C19H23Cl2N3O7: C, 47.91%, H, 4.87% N,8.82%.The crystal structure of [Cu(meophdpa)Cl(H2O)](ClO4) ÆH2O, 1, is shown in Fig. 4 [5]. Selected bond lengths (A˚)and angles () are given in Table 1. The copper atom isbonded to the three nitrogens of the meophdpa ligand, achloride and a water molecule in a distorted square-pyra-midal arrangement. The water molecule is also hydrogenbonded to a second water molecule and that molecule isin turn hydrogen bonded to the perchlorate anion. Further-more, the proton on C18 of the phenyl ring is located at adistance of 2.417 (A˚) from the copper atom, which is lessthan the sum of the Van der Waals radii for these twoatoms and hence must be considered as a reasonably stronginteraction [6]. Thus, a pseudo-octahedral geometry isobserved for the central metal. No other interactions aboutthe copper are observed, which is interesting, since copper–chloride bridging might have been expected. However, theposition of the phenyl ring precludes such bridging interac-tions on steric grounds.Fig. 4. X-ray crystal structure of [Cu(meophdpa)Cl(H2O)](ClO4) Æ H2O, 1.Ellipsoids are represented at the 30% probability level.Table 1Selected bond distances (A˚) and angles () for 1Cu(1)–N(3) 1.989(2) Cu(1)–N(1) 1.994(2)Cu(1)–N(2) 2.078(2) Cu(1)–O(5) 2.234(2)Cu(1)–Cl(1) 2.2539(7) Cl(2)–O(2) 1.395(3)Cl(2)–O(1) 1.428(2) Cl(2)–O(4) 1.433(2)Cl(2)–O(3) 1.449(3) O(7)–C(16) 1.360(3)O(7)–C(19) 1.433(4) N(2)–C(6) 1.490(3)N(2)–C(7) 1.491(3)N(3)–Cu(1)–N(1) 163.83(9) N(3)–Cu(1)–N(2) 82.01(9)N(1)–Cu(1)–N(2) 81.94(9) N(3)–Cu(1)–O(5) 93.84(9)N(1)–Cu(1)–O(5) 88.45(8) N(2)–Cu(1)–O(5) 105.30(9)N(3)–Cu(1)–Cl(1) 96.99(7) N(1)–Cu(1)–Cl(1) 97.91(7)N(2)–Cu(1)–Cl(1) 150.04(6) O(5)–Cu(1)–Cl(1) 104.64(7)C(16)–O(7)–C(19) 116.9(2) C(1)–N(1)–C(5) 119.3(2)C(1)–N(1)–Cu(1) 126.01(18) C(5)–N(1)–Cu(1) 114.62(17)C(13)–N(2)–C(6) 111.7(2) C(13)–N(2)–C(7) 111.7(2)C(6)–N(2)–C(7) 112.8(2) C(13)–N(2)–Cu(1) 109.67(15)C(6)–N(2)–Cu(1) 105.93(15) C(7)–N(2)–Cu(1) 104.62(15)C(8)–N(3)–C(12) 119.3(2) C(8)–N(3)–Cu(1) 114.44(18)C(12)–N(3)–Cu(1) 126.19(19) N(1)–C(1)–C(2) 121.8(3)Fig. 5. Packing diagram for 1, showing hydrogen-bonding interactions inthe lattice.B.S. Creaven et al. / Inorganic Chemistry Communications 9 (2006) 231–234 233The three nitrogen atoms of the meophdpa ligand exhi-bit a meridional type of coordination at copper, whereasstructures of complexes containing these ligand types showalmost exclusively facial coordination of the ligands [4,8].This coordination type observed here is unusual for struc-tures of complexes containing bis(picolyl)amine and N-substituted bis(picolyl)amine, with only two previousexamples reported for copper(II) complexes [7]. The struc-ture of Cu(phdpa)Cl2 [7b], which relates directly to that of1, consists of discrete copper(II) neutral complexes with themetal atom being five-coordinated to three nitrogens fromthe terdentate phdpa species and two chloride ions. One ofthe pyridine nitrogens therein is involved in an intramolec-ular hydrogen bond with one of the aniline protons, aninteraction replaced by a H–Cu interaction in 1. Thepseudo-planar nature of the nitrogen donor atoms in 1forces the phenyl ring attached to N(2) to be positionedin a manner that maintains the expected bond angle of106.98 as found in ammonia. There are two water mole-cules present in the lattice; one of which is ligated to thecopper and hydrogen bonded to the second water mole-cule, while this second water molecule is further hydrogenbonded to the perchlorate anion. The copper–Owater bonddistance of 2.234(2) (A˚), while being longer than that pre-viously reported for [Cu2(tpbd)(H2O)4](S2O6)2 [7] at2.170(5) (A˚), where tpbd = N,N,N 0,N 0-tetrakis(2-pyr-idylmethyl)benzene-1,4-diamine, can be rationalised interms of the other bonding interactions in the structure.Fig. 5 illustrates the lattice hydrogen bonding betweenthe water molecules and the perchlorate anions whichafford supramolecular hydrogen bonded sheets in the array[9]. There are no interactions between adjacent copperatoms.In summary, a new pyridine–amine ligand (meophdpa)has been synthesised and characterised. This ligand wasreacted with copper(II) perchlorate and the resulting com-plex analysed. The X-ray crystal structure revealed thatthe motif consists of a monomeric copper(II) site, withthe copper bound to the three nitrogens of the ligand ina relatively unusual meridional fashion, as well as a chlo-ride and a water molecule. The sixth coordination site isoccupied by a Cu–H bond of the phenyl ring. The pack-ing diagram of the structure reveals extensive hydrogen-bonding.Appendix A. Supplementary dataCrystallographic data for the structural analysis on[Cu(meophdpa)Cl(H2O)2](ClO4) have been deposited withthe Cambridge Crystallographic Data Centre, CCDC No.286615. Copies of this information may be obtained freeof charge from deposit@ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk. Supplementary data associated withthis article can be found, in the online version, atdoi:10.1016/j.inoche.2005.11.008.References[1] (a) B.-H. Ye, M.-L. Tong, X.-M. Chen, Coord. Chem. Rev. 249(2005) 545;(b) A.M. Beatty, Coord. Chem. Rev. 246 (2003) 131;(c) O. Mamula, A. von Zelewsky, Coord. Chem. Rev. 242 (2003) 87;(d) S.G. Telfer, R. Kuroda, Coord. Chem. Rev. 242 (2003) 33.[2] (a) C.J. Elsevier, J. Reedijk, P.H. Walton, M.D. Ward, J. Chem. Soc.,Dalton Trans. (2003) 1869;(b) D.L. Caulder, K.N. Raymond, Acc. Chem. Res. 32 (1999) 975;(c) D.W. Bruce, D. OHare, Inorganic Materials, Wiley, Chichester,1996;(d) F. Vo¨gtle, Supramolecular Chemistry, Wiley, Chichester, 1991.234 B.S. Creaven et al. / Inorganic Chemistry Communications 9 (2006) 231–234[3] (a) B.S. Creaven, T.L. Gernon, T. McCormac, J. McGinley, A.-M.Moore, H. Toftlund, Inorg. Chim. Acta 358 (2005) 2661;(b) D. Tobin, B.S. Creaven, C. McKenna, M. Deasy, B.A. Murray,Eur. J. Inorg. Chem. (2005) 1282;(c) B.S. Creaven, M. Deasy, J.F. Gallagher, J. McGinley, B.A.Murray, Tetrahedron 57 (2001) 8883;(d) M. Pitarch, A. Walker, J.F. Malone, J.J. McGarvey, M.A.McKervey, B. Creaven, D. Tobin, Gazz. Chim. Ital. 127 (1997) 717.[4] (a) A. Hazell, R. Hazell, C.J. McKenzie, L.P. Nielsen, J. Chem. Soc.,Dalton Trans. (2003) 2203;(b) A. Hazell, C.J. McKenzie, L.P. Nielsen, Polyhedron 19 (2000)1333.[5] Crystal data: C19H23Cl2CuN3O7,M = 539.84, triclinic, a = 8.9580(3),b = 9.1280(3), c = 13.8440(6) A˚, a = 86.258(1), b = 81.881(1),c = 86.341(2) , U = 1116.56(7) A˚3, space group P-1 (No. 2), Z = 2,l(Mo Ka) = 1.264 mm1. Crystallographic measurements were madeat 150(2) K on a Nonius kappaCCD diffractometer in the range 3.54< h < 27.57. The solution of the structure (SHELXS-86) [10] andrefinement (SHELXL-97) [11] converged to a conventional [i.e. basedon 4233F data with Fo > 4(Fo)]R1 = 0.0444 and wR2 = 0.1090.Goodness of fit = 1.064.[6] J.E. Huheey, Inorganic Chemistry, Principles of Structure andReactivity, Longman, 1993.[7] (a) T. Buchen, A. Hazell, L. Jessen, C.J. McKenzie, L.P. Nielsen, J.Z.Pedersen, D. Schollmeyer, J. Chem. Soc., Dalton Trans. (1997) 2697;(b) F. Ugozzoli, C. Massera, A.M. Manotti Lanfredi, N. Marsich, A.Camus, Inorg. Chim. Acta 340 (2002) 97.[8] (a) A. Hazell, K.B. Jensen, C.J. McKenzie, O. Simonsen, H. Toftlund,Inorg. Chim. Acta 257 (1997) 163;(b) S. Pal, M.M. Olmstead, W.H. Armstrong, Inorg. Chem. 34 (1995)4708;(c) M. Palaniandavar, T. Pandiyan, M. Laksminarayanan, H.Manohar, J. Chem. Soc., Dalton Trans. (1995) 455;(d) S. Pal, M.K. Chan, W.H. Armstrong, J. Am. Chem. Soc. 114(1992) 6398;(e) J. Glerup, P.A. Goodson, D.J. Hodgson, K. Michelsen, K.M.Nielsen, H. Wiehe, Inorg. Chem. 31 (1992) 4611;(f) R.J. Butcher, A.W. Addison, Inorg. Chim. Acta 158 (1989) 211;(g) S. Larsen, K. Michelsen, E. Pedersen, Acta Chem. Scand. 40(1986) 63.[9] P. McArdle, J. Appl. Crystallogr. 28 (1995) 65.[10] G.M. Sheldrick, in: SHELXS-86, A Computer Program for CrystalStructure Determination, University of Go¨ttingen, Go¨ttingen,1986.[11] G.M. Sheldrick, in: SHELXL-97, A Computer Program for CrystalStructure Refinement, University of Go¨ttingen, Go¨ttingen, 1997.

Copper(11) complex of a tridentate N-Donor ligand with unexpected Cu-H interaction

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Copper(11) complex of a tridentate N-Donor ligand with unexpected Cu-H interaction

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